Since no one else seems to be growing these, I'll jump in so you don't think you're talking to yourself!

I've never grown these myself but they seem to do well enough with a nice hot summer. I saw a few blooming in a garden last fall in October and they were nice. I'm not sure how many you would need to plant in order to get enough foliage for privacy though since a single root doesn't seem to produce a very thick plant. Have you considered something like morning glories, spanish flag, or moon flowers?

Thank you for your reply! My first thought was, noone wanted to reply and then realized that maybe noone has grown them. I grew morning glories last year and they were beautiful until the extreme heat made their leaves look horrible so I am not growing them this year. Hopefully there won't be volunteers everywhere from all the seeds they dropped and didn't get picked up during the cleanup. I have never heard of spanish flag so I will look them up.

I do have 3 clematis but they are young, so they probably won't cover much this year. Maybe I could grow the gloriosa lily together with some scarlet runner beans?

I have grown them for several years in pots. They are an interesting plant, but not very full and would not recommend them for an out door plant to cover anything. Al